// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_DISK_CACHE_SIMPLE_SIMPLE_UTIL_H_
#define NET_DISK_CACHE_SIMPLE_SIMPLE_UTIL_H_

#include <stdint.h>

#include <string>

#include "base/strings/string_piece.h"
#include "net/base/net_export.h"

namespace base {
class FilePath;
class Time;
}

namespace disk_cache {

namespace simple_util {

    NET_EXPORT_PRIVATE std::string ConvertEntryHashKeyToHexString(
        uint64_t hash_key);

    // |key| is the regular cache key, such as an URL.
    // Returns the Hex ascii representation of the uint64_t hash_key.
    NET_EXPORT_PRIVATE std::string GetEntryHashKeyAsHexString(
        const std::string& key);

    // |key| is the regular HTTP Cache key, which is a URL.
    // Returns the hash of the key as uint64_t.
    NET_EXPORT_PRIVATE uint64_t GetEntryHashKey(const std::string& key);

    // Parses the |hash_key| string into a uint64_t buffer.
    // |hash_key| string must be of the form: FFFFFFFFFFFFFFFF .
    NET_EXPORT_PRIVATE bool GetEntryHashKeyFromHexString(
        const base::StringPiece& hash_key,
        uint64_t* hash_key_out);

    // Given a |key| for a (potential) entry in the simple backend and the |index|
    // of a stream on that entry, returns the filename in which that stream would be
    // stored.
    NET_EXPORT_PRIVATE std::string GetFilenameFromKeyAndFileIndex(
        const std::string& key,
        int file_index);

    // Same as |GetFilenameFromKeyAndIndex| above, but using a hex string.
    std::string GetFilenameFromEntryHashAndFileIndex(uint64_t entry_hash,
        int file_index);

    // Given a |key| for an entry, returns the name of the sparse data file.
    std::string GetSparseFilenameFromEntryHash(uint64_t entry_hash);

    // Given the size of a key, the size in bytes of the header at the beginning
    // of a simple cache file.
    size_t GetHeaderSize(size_t key_length);

    // Given the size of a file holding a stream in the simple backend and the key
    // to an entry, returns the number of bytes in the stream.
    NET_EXPORT_PRIVATE int32_t GetDataSizeFromFileSize(size_t key_length,
        int64_t file_size);

    // Given the size of a stream in the simple backend and the key to an entry,
    // returns the number of bytes in the file.
    NET_EXPORT_PRIVATE int64_t GetFileSizeFromDataSize(size_t key_length,
        int32_t data_size);

    // Given the stream index, returns the number of the file the stream is stored
    // in.
    NET_EXPORT_PRIVATE int GetFileIndexFromStreamIndex(int stream_index);

    // Fills |out_time| with the time the file last modified time. Unlike the
    // functions in file.h, the time resolution is milliseconds.
    NET_EXPORT_PRIVATE bool GetMTime(const base::FilePath& path,
        base::Time* out_mtime);

    // Deletes a file, insuring POSIX semantics. Provided that all open handles to
    // this file were opened with File::FLAG_SHARE_DELETE, it is possible to delete
    // an open file and continue to use that file. After deleting an open file, it
    // is possible to immediately create a new file with the same name.
    NET_EXPORT_PRIVATE bool SimpleCacheDeleteFile(const base::FilePath& path);

} // namespace simple_util

} // namespace disk_cache

#endif // NET_DISK_CACHE_SIMPLE_SIMPLE_UTIL_H_
